If you have ever been involved with the Occult you need deliverance. If you struggle with mental issues, depression, sadness, anxiety, fears of all sorts you may need deliverance. If you read your Bible, praise and worship God, and have a healthy, active prayer life but are still in bondage to things such as food, drugs, alcohol, shopping, pornography, etc. you need deliverance. If you cannot quit sinning you need deliverance.

"But when people keep on sinning, it shows that they belong to the devil, who has been sinning since the beginning. But the Son of God came to destroy the works of the devil (1 John 3:8" NLT).

Yes He did! When Jesus said "it is finished" He meant the atonement, the blood sacrifice for sin was finished. Never again does anyone have to die for their own sins, if they so choose to believe in Him who the Father (God) sent. However, we as followers of Christ must appropriate the Blood of Jesus Christ to our lives, much like Moses was to take the lamb and slaughter it, along with all the other Isrealites, and apply the blood to the doorposts (Exodus 12:7), we must apply the Blood to our lives. Thirty percent of Jesus' ministry was casting out demons! If it wasn't relevant then why did He do it and why did He teach His disciples to do the same?
17 And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues; 18 They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover (Mark 16:17-18 KJV).
“Heal the sick, cleanse the lepers, raise the dead, cast out demons. Freely you have received, freely give" (Matt 10:8 NKJV).
Then He called His twelve disciples together and gave them power and authority over all demons, and to cure diseases (Luke 9:1).

Deliverance is for Believers of Jesus Christ. Anyone who wants to be delivered from any form of oppression or addiction must understand who the Deliverer is, Jesus Christ. We are ambassadors of Christ and as such Jesus said we would do the works He did. "Verily, verily, I say unto you, he that believeth on me, the works that I do shall he do also; and greater works than these shall he do; because I go unto the Father." (John 14:12 ASV). We do the works of Jesus Christ but it is He that ultimately sets us free. If a person doesn't believe in Jesus Christ then they have no reason to believe they can be set free by Him. So if the Son sets you free, you will be free indeed (John 8:36 NIV).